1. Field of the Invention
The present invention relates to an electrical device such as an image forming apparatus (for example, a copier, a printer, or a facsimile (FAX)).
2. Description of the Related Art
Inside an electrophotographic image forming apparatus, a voltage higher than an alternating-current voltage of a commercial power supply has been used. Meanwhile, there have been cases where an operator opens a door provided on an image forming apparatus in order to replace cartridges or remove jammed sheets. Moreover, there are gears or the like that are rotated by a motor inside an image forming apparatus. Accordingly, an interlock mechanism for shutting off a current supplied from a power supply circuit when a door is opened has been adopted. The current supplied from the power supply circuit is thus shut off when the door is opened. Sometimes a relay and an interlock switch are provided as an interlock mechanism. The interlock switch is turned off when the door is opened, and the contact of the relay is opened in conjunction with the turning off of the switch, thereby stopping the supply of the current.
Incidentally, there are cases where a power supply line or a signal line such as that of a CPU are arranged near a line to a drive terminal of an interlock switch or a relay. When these lines short-circuit, the contact of the relay sometimes remains closed despite the door being open. In Japanese Patent Laid-Open No. 2007-152646, a distance between these lines is longer than a common insulation distance so that short-circuiting between lines are less likely to occur.
However, the longer the distance between the lines is, the larger the size of the circuit board becomes.